(Reuters) - Often praised for doing the dirty, understated work in midfield, Real Madrid's Casemiro is taking on an increasingly influential role for Zinedine Zidane's side and stamped his mark all over Saturday's crucial 2-1 win at Athletic Bilbao in La Liga.

The Brazilian midfielder was the architect of Real's opener against Athletic, who had not lost at home since August, splitting the defence with a long ball from the halfway line to Cristiano Ronaldo, who crossed for Karim Benzema to score.

Athletic fought to get back into the game and pulled level through veteran strike Aritz Aduriz, only for Casemiro to restore Real's lead three minutes later by losing his marker from a corner to meet Ronaldo's flicked header.

It was the Brazilian's third goal of 2017, adding to his thunderous volley against Napoli and his strike against Granada and tripling his tally from last season.

It also cemented Real's bid to land a first league title since 2012, taking them five points clear of nearest chalengers Barcelona -- who host Valencia on Sunday -- at the top of the standings.

"Casemiro has grown in a spectacular way. He works very hard and it's a privilege to play with him for club and country as he's one of the best midfielders in the world," Real defender Marcelo told reporters on Saturday.

Zidane had rested Casemiro in two of Real's last three league games. His importance was laid bare in the chaotic 3-3 draw against Las Palmas and the unconvincing 2-1 win over Real Betis last Sunday, and he gave them more resilience when they needed it most against Athletic.

The Brazilian will miss next week's game against Alaves through suspension after picking up a yellow card in the first half and showed his humility by expressing his anxiety about losing his place in the team.

"I didn't think it was a yellow card and I didn't want to miss the Alaves game because with the quality we have, if you give an opportunity to another player they can take your place in the team," Casemiro said.

While there is plenty of competition between creative players, illustrated by the fact both Isco and James Rodriguez have started less than half Real's league games, there is no other player in the squad who can do what Casemiro does, and he can expect to slot right back into the starting 11 when he completes his suspension.